Dollarweed (Hydrocotyle spp.), also known as pennywort, is a warm-season perennial weed. It gets the common name, dollarweed, from its… Dollar weed,is a perennial weed that commonly pops up in moist lawns and gardens. This weed is often difficult to control once it becomes well established. Find out how to control it here.
Dollarweed (Hydrocotyle spp.), also known as pennywort, is a warm-season perennial weed. It gets the common name, dollarweed, from its silver
–dollar-shaped leaves. The leaves of dollarweed are round, bright green, fleshy, and look like miniature lily pads measuring 1-2” in diameter with a scalloped edge. It has a low-growing habit that spreads by seeds, rhizomes, and tubers.
Dollarweed is often confused with dichondra. One way to distinguish the two is by looking at the placement of the leaf stem. Dollarweed has a stem located in the center of the leaf, while dichondra’s stem is located at the edge (see image below).
Dollarweed leaf on the left and dichondra leaf on the right.
Bert McCarty, ©Clemson University
Before starting a weed control program, homeowners should realize that the complete eradication of dollarweed (or any weed) from the landscape is not practical. Instead, a more realistic approach is to control (not eradicate) the weed by limiting the infestation to a tolerable level.
Dollarweed is a water-loving plant that can float. The presence of dollarweed indicates that there is excessive moisture in the area. Research at the University of Florida demonstrated a reduction in dollarweed just by reducing irrigation frequency (http://grove.ufl.edu/~turf/weeds/dollarweed.html). Monitoring moisture levels and evaluating irrigation frequency are the first steps to controlling dollarweed. Established landscape plants and lawns require one inch of water a week for optimum growth.
A properly maintained landscape that is not stressed by insects, diseases, drought, or nutrient imbalance is the best defense against weeds. Proper mowing height of lawns and a 3-inch thick mulch layer around trees and shrubs will prevent the invasion of weeds. For more information on proper landscape maintenance techniques, see the following fact sheets: HGIC 1056, Watering Trees & Shrubs; HGIC 1604, Mulch; HGIC 1201, Fertilizing Lawns; HGIC 1205, Mowing Lawns; and HGIC 1207, Watering Lawns.
Lawns: Dollarweed thrives in weak, thin turf with excessive moisture. The first defense against dollarweed is to reduce moisture levels and modify cultural methods (i.e., proper mowing height and irrigation). After taking steps to modify the lawn care techniques, a chemical control may still be necessary to reduce the dollarweed population further. Herbicides should be chosen according to turf species and applied in late spring (after full spring green-up of the lawn) when weeds are small. Herbicide effectiveness is reduced as weeds mature.
Atrazine can be applied to St. Augustinegrass and centipedegrass up to two times a year. For maximum effect, atrazine should be applied once in the fall and again in late spring (after spring green-up). Atrazine has a pre-and post-emergent effect on weeds, which means it helps to control both emerged weeds and weed seed. It should NOT be applied to newly seeded lawns due to the detrimental effect it has on seed germination. Delay atrazine applications to newly sodded and sprigged lawns until it is well-established and actively growing. Examples of products containing atrazine in homeowner sizes are:
- Hi-Yield Atrazine Weed Killer
- Southern Ag Atrazine St Augustine Weed Killer
Dollarweed in a lawn.
Bert McCarty, ©Clemson University
A three-way herbicide may be used safely on bermudagrass, zoysiagrass, centipedegrass, St. Augustinegrass, and tall fescue. The active ingredients of a three-way herbicide include the following broadleaf weed killers: 2,4- D, dicamba, and mecoprop (MCPP) or MCPA. Examples of three-way herbicides in homeowner sizes are:
- Ferti-lome Weed-Out Lawn Weed Killer – Contains Trimec ®
- Southern Ag Lawn Weed Killer with Trimec ®
- Bayer BioAdvanced Southern Weed Killer for Lawns Concentrate; or RTS
- Spectracide Weed Stop Weed Killer for Lawns Concentrate; or RTS
- Bonide Weed Beater – Lawn Weed Killer Concentrate
- Ortho Weed B Gon Weed Killer for Lawns Concentrate; or RTS
- Ortho WeedClear Weed Killer for Lawns Concentrate
- Gordon’s Trimec Lawn weed Killer Concentrate; & RTS
CAUTION: Herbicides containing 2,4-D should be applied at a reduced rate on St. Augustinegrass and centipedegrass to prevent damage to these lawns. The product label will give the rate to use for each type of turfgrass. If a second application is needed, apply the herbicide in spot treatments. Repeated applications of a three-way herbicide should be spaced according to label directions. Three-way herbicides should not be applied during spring transition (green-up of lawn) or when air temperatures exceed 90 ºF. Treat warm-season lawns after the turfgrass is fully green. A newly seeded lawn should be mowed a minimum of three times before applying an herbicide.
Imazaquin (such as in Image Nutsedge Killer) can be applied safely to bermudagrass, St. Augustinegrass, centipedegrass, and zoysiagrass, but do not apply to tall fescue. Apply imazaquin in the late spring (after spring green-up) when weeds are small. A second application can be made in six weeks after the initial application. Do not apply to newly planted, plugged, or sodded turfgrass.
Since both atrazine and imazaquin can travel through soil and enter groundwater, please read the label for all environmental precautions. Users are advised not to apply atrazine or imazaquin to sand or loamy sand soils where the water table (groundwater) is close to the surface and where these soils are very permeable, i.e., well-drained.
The herbicide mix of thiencarbazone, iodosulfuron, and dicamba, as found in Celsius WG Herbicide, is selective to control many broadleaf weeds and several grass weeds in all four of the common warm-season grasses. It cannot be used on fescue lawns but can be used to remove fescue from warm-season lawns. Apply when dollarweed is actively growing and again 2 to 4 weeks later. The addition of a non-ionic surfactant (such as Southern Ag Surfactant for Herbicides, Hi-Yield Spreader Sticker, or Bonide Turbo Spreader Sticker) will increase control (see Table 1).
Once dollarweed has been eliminated in areas of the turf, bare spots will be left behind. To prevent the invasion of new weeds in these bare spots fill them with plugs or sprigs of the desired turfgrass. Fertilize the lawn based on soil report recommendations.
Table 1. Turf Tolerance to Herbicides for Dollarweed Control.
Landscape Beds: In landscape beds, dollarweed can be hand dug or controlled with an herbicide. Dollarweed is a perennial weed that can emerge from seeds, tubers, and rhizomes. Once dollarweed has made its way into the landscape bed, an herbicide may be necessary if hand pulling is not practical.
Glyphosate can be used for spot treatments around ornamental plants. Glyphosate is a non-selective herbicide that should be used with caution. Spray with a 3% Glyphosate solution in a pump-up sprayer for dollarweed control. Follow label directions for mixing and use. Do not allow glyphosate spray mist to contact ornamental foliage or stems, as severe injury will occur. A cardboard shield may be used to prevent glyphosate spray from drifting to nearby ornamentals. Examples of products containing glyphosate in homeowner sizes are:
- Roundup Original Concentrate,
- Roundup Pro Herbicide,
- Martin’s Eraser Systemic Weed & Grass Killer,
- Quick Kill Grass & Weed Killer,
- Bonide Kleenup Weed & Grass Killer 41% Super Concentrate,
- Hi-Yield Super Concentrate,
- Maxide Super Concentrate 41% Weed & Grass Killer,
- Super Concentrate Killzall Weed & Grass Killer,
- Tiger Brand Quick Kill Concentrate,
- Ultra Kill Weed & Grass Killer Concentrate,
- Gordon’s Groundwork Concentrate 50% Super Weed & Grass Killer,
- Zep Enforcer Weed Defeat III,
- Eliminator Weed & Grass Killer Super Concentrate,
- Monterey Remuda Full Strength 41% Glyphosate,
- Knock Out Weed & Grass Killer Super Concentrate,
- Southern States Grass & Weed Killer Concentrate II,
- Total Kill Pro Weed & Grass Killer Herbicide,
- Ace Concentrate Weed & Grass Killer.
Imazaquin (as in Image Nutsedge Killer) is a selective herbicide that can be applied safely around certain landscape plants; see product label for a listing of the tolerant plant materials. Imazaquin should not be applied around the root zones of plants that are not on the product label. It is best to apply imazaquin when weeds are small in spring. A second application can be applied six weeks later if necessary.
Glyphosate and imazaquin are both more effective when weeds are actively growing and may not work as well if applied under drought conditions. As with all pesticides, read and follow all label instructions and precautions.
Pesticides are updated annually. Last updates were done on 7/21 by Joey Williamson.
Originally published 11/08
If this document didn’t answer your questions, please contact HGIC at [email protected] or 1-888-656-9988.
Millie Davenport, Director of Home and Garden Information Center, Horticulture Program Team, Clemson University
Joey Williamson, PhD, HGIC Horticulture Extension Agent, Clemson University
This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.
Eliminate Dollar Weed – How To Kill Dollar Weed
Dollar weed (Hydrocotyle spp.), also known as pennywort, is a perennial weed that commonly pops up in moist lawns and gardens. Similar in appearance to lily pads (only smaller with white flowers), this weed is often difficult to control once it becomes well established. In fact, it can quickly spread throughout the lawn and other areas by seed and rhizomes. Nonetheless, there are several options available to treat dollar weed should it become a problem for you.
Getting Rid of Dollar Weed Naturally
Since this weed thrives in overly moist areas, the best way to treat dollar weed is by reducing moisture in the affected area with proper mowing and irrigation. You should also improve any drainage issues that may be present.
In addition, dollar weed can be easily pulled up by hand, though this can be tedious and in larger areas, it may not be feasible. Organic control involves methods that may work for some while not others, but it’s always worth a try to see if one will work for you before resorting to chemicals. These methods include the following:
- Boiling water – Pouring boiling water on areas with dollar weed will quickly kill the plants. However, care should be taken not to get any on other nearby plants or grass, as boiling water will kill anything it comes into contact with.
- Baking soda – Some people have had luck with using baking soda for killing dollar weeds. Simply wet down the dollar weed foliage and sprinkle baking soda over it, leaving it overnight. This is supposed to kill the weeds but be safe for the grass.
- Sugar – Others have found success with dissolving white sugar over the weed. Spread the sugar over the area and water it in thoroughly.
- Vinegar – Spot treating dollar weed with white vinegar has also been deemed effective as a dollar weed herbicide.
How to Kill Dollar Weed with Chemicals
Sometimes chemical control is necessary for killing dollar weeds. Most types of dollar weed herbicide are applied in spring while the plants are still young, though repeat applications may be needed. Monument, Manor, Blade, Image, and Atrazine have all been found to effectively eradicate this weed. They are also safe for use on Zoysia, St. Augustine, Bermuda, and Centipede grasses (provided you carefully follow instructions).
Note: Chemical control should only be used as a last resort, as organic approaches are safer and much more environmentally friendly.